<template>
    <div class='Panorama'>
        <div class="container">
             <div ref="container" id="container"></div>
        </div>
    </div>
</template>

<script>
// import * as THREE from 'three'
export default {
  name: 'Panorama',
  data () {
    return {
      sceneUrl: 'https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fimg.zcool.cn%2Fcommunity%2F0165705e708710a80120a89594a78a.jpg%401280w_1l_2o_100sh.jpg&refer=http%3A%2F%2Fimg.zcool.cn&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=auto?sec=1672819559&t=bc32530528423980322973cb5eeb1979', // 需要预览的图片绝对路径
      camera: null,
      scene: null,
      renderer: null,
      isUserInteracting: false,
      onPointerDownPointerX: 0,
      onPointerDownPointerY: 0,
      lon: 0,
      onPointerDownLon: 0,
      lat: 0,
      onPointerDownLat: 0,
      phi: 0,
      theta: 0,
      target: new THREE.Vector3()
    }
  },
  mounted() {
    this.init();
  },
  methods: {
    init() {
      let textureLoader = new THREE.TextureLoader();
      textureLoader.load(this.sceneUrl, (texture) => {
        texture.mapping = THREE.UVMapping;
        this.initImg(texture);
        this.render();
      });
    },
    initImg(texture) {
      let container, mesh;
      // 容器宽度、高度
      let containerWidth = this.$refs.container.offsetWidth;
      let containerHeight = this.$refs.container.offsetHeight;
      container = document.getElementById('container');
      this.renderer = new THREE.WebGLRenderer({ antialias: true });
      this.renderer.setPixelRatio(window.devicePixelRatio);
      // this.renderer.setSize(window.innerWidth, window.innerHeight);
      this.renderer.setSize(containerWidth, containerHeight);
      let childs = container.childNodes;
      if (container.childNodes.length > 0) {
        container.removeChild(childs[0]);
        container.appendChild(this.renderer.domElement);
      } else {
        container.appendChild(this.renderer.domElement);
      }

      this.scene = new THREE.Scene();
      this.camera = new THREE.PerspectiveCamera(60, containerWidth  / containerHeight , 1, 1000);
      mesh = new THREE.Mesh(new THREE.SphereBufferGeometry(500, 32, 16), new THREE.MeshBasicMaterial({ map: texture }));
      mesh.geometry.scale(-1, 1, 1);
      this.scene.add(mesh);

      container.addEventListener('mousedown', this.onDocumentMouseDown, false);
      container.addEventListener('mousemove', this.onDocumentMouseMove, false);
      container.addEventListener('mouseup', this.onDocumentMouseUp, false);
      container.addEventListener('mousewheel', this.onDocumentMouseWheel, false);

      container.addEventListener('touchstart', this.onDocumentTouchStart, false);
      container.addEventListener('touchmove', this.onDocumentTouchMove, false);
    },
    onDocumentMouseDown(event) {
      event.preventDefault();
      this.isUserInteracting = true;
      this.onPointerDownPointerX = event.clientX;
      this.onPointerDownPointerY = event.clientY;
      this.onPointerDownLon = this.lon;
      this.onPointerDownLat = this.lat;
    },

    onDocumentMouseMove(event) {
      if (this.isUserInteracting) {
        this.lon = (this.onPointerDownPointerX - event.clientX) * 0.1 + this.onPointerDownLon;
        this.lat = (event.clientY - this.onPointerDownPointerY) * 0.1 + this.onPointerDownLat;
        this.render();
      }
    },

    onDocumentMouseUp(event) {
      this.isUserInteracting = false;
      this.render();
    },

    onDocumentMouseWheel(event) {
      this.camera.fov -= event.wheelDeltaY * 0.05;
      this.camera.updateProjectionMatrix();
      event = event || window.event;
      if (event.stopPropagation) { // 这是取消冒泡
        event.stopPropagation();
      } else {
        event.cancelBubble = true;
      };
      if (event.preventDefault) { // 这是取消默认行为
        event.preventDefault();
      } else {
        event.returnValue = false;
      };
      this.render();
    },

    onDocumentTouchStart(event) {
      if (event.touches.length == 1) {
        event.preventDefault();
        this.onPointerDownPointerX = event.touches[0].pageX;
        this.onPointerDownPointerY = event.touches[0].pageY;
        this.onPointerDownLon = this.lon;
        this.onPointerDownLat = this.lat;
      }
    },

    onDocumentTouchMove(event) {
      if (event.touches.length == 1) {
        event.preventDefault();
        this.lon = (this.onPointerDownPointerX - event.touches[0].pageX) * 0.1 + this.onPointerDownLon;
        this.lat = (event.touches[0].pageY - this.onPointerDownPointerY) * 0.1 + this.onPointerDownLat;
        this.render();
      }
    },
    render() {
      this.lon += 0.15;
      this.lat = Math.max(-85, Math.min(85, this.lat));
      this.phi = THREE.Math.degToRad(90 - this.lat);
      this.theta = THREE.Math.degToRad(this.lon);
      this.camera.position.x = 100 * Math.sin(this.phi) * Math.cos(this.theta);
      this.camera.position.y = 100 * Math.cos(this.phi);
      this.camera.position.z = 100 * Math.sin(this.phi) * Math.sin(this.theta);
      this.camera.lookAt(this.scene.position);
      this.renderer.render(this.scene, this.camera);
    }
  }
}
</script>

<style lang='scss' scoped>

 #container{
    width: 100%;
     height: 600px;
     background: #eee;}
</style>
